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Xiao-Li Sun, Dong-Ming Liu, Pan Wang, Jia-Lin Tan, Kang-Kang Li, Li Deng, Wen-Ming Wan
The morphology library of block copolymer (BCP) self-assemblies is limited, especially as far as tubular structures are concerned. Here, the morphology of clews of tubules is discovered for the first time by self-assembly of P4VP-b-PS BCPs with both high asymmetry and very high molecular weight, which successfully expands the morphology library of BCP self-assemblies.
April 20, 2017: Chemical Communications: Chem Comm
Prisca M J Theunissen, Lukasz Sedek, Valerie De Haas, Tomasz Szczepanski, Alita Van Der Sluijs, Ester Mejstrikova, Michaela Nováková, Tomas Kalina, Quentin Lecrevisse, Alberto Orfao, Arjan C Lankester, Jacques J M van Dongen, Vincent H J Van Der Velden
Flow cytometric detection of minimal residual disease (MRD) in children with B-cell precursor acute lymphoblastic leukaemia (BCP-ALL) requires immunophenotypic discrimination between residual leukaemic cells and B-cell precursors (BCPs) which regenerate during therapy intervals. In this study, EuroFlow-based 8-colour flow cytometry and innovative analysis tools were used to first characterize the immunophenotypic maturation of normal BCPs in bone marrow (BM) from healthy children, resulting in a continuous multiparametric pathway including transition stages...
April 17, 2017: British Journal of Haematology
Dong Hyup Kim, So Youn Kim
Over the past several decades, tremendous efforts have been made to understand the fundamental physics of block copolymer (BCP) self-assembly in bulk or thin films, and this has led to the development of BCP-based bottom-up nanofabrication. BCPs also form periodic nanostructures at the air/water interface, which has potential application to ultrathin-film nanopatterning with molecular-level precision. Nonetheless, controlling the nanostructure formation at the air/water interface is restricted by the inherent parameters of BCPs; BCP morphology is determined by the hydrophilic-to-hydrophobic block ratio...
April 20, 2017: Journal of Physical Chemistry Letters
Ben Liu, Srinivas Thanneeru, Aaron Lopes, Lei Jin, Meghan McCabe, Jie He
New synthetic methods capable of controlling structural and compositional complexities of asymmetric nanoparticles (NPs) are very challenging but highly desired. A simple and general synthetic approach to designing sophisticated asymmetric NPs by anisotropically patterning the surface of isotropic metallic NPs with amphiphilic block copolymers (BCPs) is reported. The selective galvanic replacement and seed-mediated growth of a second metal can be achieved on the exposed surface of metal NPs, resulting in the formation of nanobowls and Janus-type metal-metal dimers, respectively...
April 3, 2017: Small
Yutaka Tsubomoto, Satoko Hayashi, Waro Nakanishi, Takahiro Sasamori, Norihiro Tokitoh
The nature of E2X2 σ(4c-6e) of the X-*-E-*-E-*-X type is elucidated for 1-(8-XC10H6)E-E(C10H6X-8')-1' [(1) E, X = S, Cl; (2) S, Br; (3) Se, Cl; (4) Se, Br] after structural determination of (1), (3) and (4), together with model A [MeX---E(H)-E(H)---XMe (E = S and Se; X = Cl and Br)]. The quantum theory of atoms-in-molecules dual functional analysis (QTAIM-DFA) is applied. The total electron energy densities Hb(rc) are plotted versus Hb(rc) - Vb(rc)/2 for the interactions at the bond critical points (BCPs; *), where Vb(rc) show the potential energy densities at the BCPs...
April 1, 2017: Acta Crystallographica Section B, Structural Science, Crystal Engineering and Materials
Kevin Wylie, Ian Bennett, Milan Marić
The effect of diffuse compositional interfaces on copolymer self-assembly was studied via gradient copolymers (GCP). Poly(methyl methacrylate)-grad-(styrene) (PMMA-grad-PSt) copolymers were synthesized in semi-batch mode using nitroxide-mediated polymerization (NMP) with varied monomer injection protocols to produce varied diffuse interfaces (number average molecular weights (Mn) ranged from 62 000 g mol(-1) to 94 000 g mol(-1) with dispersities (Đ) between 1.35 and 1.59). The GCPs were spun into thin films on substrates made neutral by (St-ran-MMA-ran-hydroxyethyl methacrylate) terpolymers and annealed at elevated temperature to produce vertically oriented microphase-separated domains...
April 12, 2017: Soft Matter
Kenta Imai, Masaya Murata, Yujiro Ide, Mikio Sugano, Hiroki Ito, Kazuyoshi Kanno, Motonori Ishido, Ryohei Fukuba, Kisaburo Sakamoto
OBJECTIVES: To review long-term outcomes of patients with right atrial (RA) isomerism who underwent common atrioventricular valve (CAVV) plasty. METHODS: We retrospectively analysed 59 patients with RA isomerism operated on between January 2004 and April 2016. We divided patients into those with CAVV plasty (CAVV plasty (+), 29 patients) and without CAVV plasty (CAVV plasty (-), 30), and we compared the outcome between the groups. We further divided patients into those with CAVV plasty before bidirectional cavopulmonary shunt (BCPS) operation (group before BCPS, 13 patients) or CAVV plasty with or after BCPS (group with or after BCPS, 16), and we compared the outcome between these groups...
May 1, 2017: European Journal of Cardio-thoracic Surgery
Ryuichi Nakatani, Hiroki Takano, Alvin Chandra, Yasunari Yoshimura, Lei Wang, Yoshinori Suzuki, Yuki Tanaka, Rina Maeda, Naoko Kihara, Shinya Minegishi, Ken Miyagi, Yuusuke Kasahara, Hironobu Sato, Yuriko Seino, Tsukasa Azuma, Hideaki Yokoyama, Christopher K Ober, Teruaki Hayakawa
In this study, a series of perpendicular lamellae-forming poly(polyhedral oligomeric silsesquioxane methacrylate-block-2,2,2-trifluoroethyl methacrylate)s (PMAPOSS-b-PTFEMAs) was developed based on the bottom-up concept of creating a simple yet effective material by tailoring the chemical properties and molecular composition of the material. The use of silicon (Si)-containing hybrid high-χ block copolymers (BCPs) provides easy access to sub-10 nm feature sizes. However, as the surface free energies (SFEs) of Si-containing polymers are typically vastly lower than organic polymers, this tends to result in the selective segregation of the inorganic block onto the air interface and increased difficulty in controlling the BCP orientation in thin films...
March 17, 2017: ACS Applied Materials & Interfaces
Xiuyu Wang, Xueyan Feng, Guiping Ma, Di Zhang, Yahong Chai, Maofa Ge, Li Yao
Block copolymers (BCPs) have the capacity to self-assemble into a myriad of well-defined aggregate structures, offering great promise for the construction of drug delivery, photolithographic templates, and complex nanoscale assemblies. A uniqueness of these materials is their propensity to become kinetically frozen in non-equilibrium states, implying that the process of self-assembly can be utilized to remodel the resulting structures. Here, a new semiconfined system for processing the BCP self-assembly is constructed, in which an unusual dual-phase separation occurs, including nonsolvent-induced microphase separation and osmotically driven macrophase separation, ultimately yielding heterogeneous BCP membranes...
March 15, 2017: Advanced Materials
Federico Ferrarese Lupi, Tommaso Jacopo Giammaria, Gabriele Seguini, Michele Laus, Pavo Dubček, Branko Pivac, Sigrid Bernstorff, Michele Perego
The morphological evolution of cylinder-forming poly(styrene)-b-poly(methyl methacrylate) block copolymer (BCP) thick films treated at high temperatures in the rapid thermal processing (RTP) machine was monitored by means of in-depth grazing-incidence small-angle X-ray scattering (GISAXS). The use of this nondisruptive technique allowed one to reveal the formation of buried layers composed of both parallel- and perpendicular-oriented cylinders as a function of the film thickness (24 ≤ h ≤ 840 nm) and annealing time (0 ≤ t ≤ 900 s)...
March 29, 2017: ACS Applied Materials & Interfaces
Satoko Hayashi, Kengo Nagata, Shota Otsuki, Waro Nakanishi
The dynamic and static nature of extended hypervalent interactions of the (B)E···(A)E···(A)E···(B)E type are elucidated for four center-seven electron interactions (4c-7e) in the radical cationic dimers (1·(+)) and 4c-6e in the dicationic dimers (1(2+)) of 1,5-(dichalcogena)canes (2: (A)E(CH2CH2CH2)2(B)E: (A)E, (B)E = S, Se, Te, and O). The quantum theory of atoms-in-molecules dual functional analysis (QTAIM-DFA) is applied for the analysis. Total electron energy densities Hb(rc) are plotted versus Hb(rc) - Vb(rc)/2 [= (ℏ(2)/8m)∇(2)ρb(rc)] at bond critical points (BCPs) of the interactions, where Vb(rc) values show potential energy densities at BCPs...
March 15, 2017: Journal of Physical Chemistry. A
Tao Wen, Hsiao-Fang Wang, Ming-Chia Li, Rong-Ming Ho
The significance of chirality transfer is not only involved in biological systems, such as the origin of homochiral structures in life but also in man-made chemicals and materials. How the chiral bias transfers from molecular level (molecular chirality) to helical chain (conformational chirality) and then to helical superstructure or phase (hierarchical chirality) from self-assembly is vital for the chemical and biological processes in nature, such as communication, replication, and enzyme catalysis. In this Account, we summarize the methodologies for the examination of homochiral evolution at different length scales based on our recent studies with respect to the self-assembly of chiral polymers and chiral block copolymers (BCPs*)...
March 3, 2017: Accounts of Chemical Research
Cong Jin, Brian C Olsen, Erik J Luber, Jillian M Buriak
Block copolymer (BCP) self-assembly is of great interest as a cost-effective method for large-scale, high-resolution nanopattern fabrication. Directed self-assembly can induce long-range order and registration, reduce defect density, and enable access to patterns of higher complexity. Here we demonstrate preferential orientation of two incommensurate BCP dot arrays. A bottom layer of hexagonal silica dots is prepared via typical self-assembly from a PS-b-PDMS block copolymer. Self-assembly of a second, or top, layer of a different PS-b-PDMS block copolymer that forms a hexagonal dot pattern with different periodicity results in a predictable moiré superstructure...
March 28, 2017: ACS Nano
Tommaso Jacopo Giammaria, Federico Ferrarese Lupi, Gabriele Seguini, Katia Sparnacci, Diego Antonioli, Valentina Gianotti, Michele Laus, Michele Perego
Block copolymers (BCPs) are emerging as a cost-effective nanofabrication tool to complement conventional optical lithography because they self-assemble in highly ordered polymeric templates with well-defined sub-20-nm periodic features. In this context, cylinder-forming polystyrene-block-poly(methyl methacrylate) BCPs are revealed as an interesting material of choice because the orientation of the nanostructures with respect to the underlying substrate can be effectively controlled by a poly(styrene-random-methyl methacrylate) random copolymer (RCP) brush layer grafted to the substrate prior to BCP deposition...
February 14, 2017: ACS Applied Materials & Interfaces
Jae Man Shin, YongJoo Kim, Hongseok Yun, Gi-Ra Yi, Bumjoon J Kim
Shape and morphology of polymeric particles are of great importance in controlling their optical properties or self-assembly into unusual superstructures. Confinement of block copolymers (BCPs) in evaporative emulsions affords particles with diverse structures, including prolate ellipsoids, onion-like spheres, oblate ellipsoids, and others. Herein, we report that the evaporation rate of solvent from emulsions encapsulating symmetric polystyrene-b-polybutadiene (PS-b-PB) determines the shape and internal nanostructure of micron-sized BCP particles...
February 28, 2017: ACS Nano
J M Bouler, P Pilet, O Gauthier, E Verron
Autologous bone graft is considered as the gold standard in bone reconstructive surgery. However, the quantity of bone available is limited and the harvesting procedure requires a second surgical site resulting in severe complications. Due to these limits, scientists and clinicians have considered alternatives to autologous bone graft. Calcium phosphates (CaPs) biomaterials including biphasic calcium phosphate (BCP) ceramics have proven efficacy in numerous clinical indications. Their specific physico-chemical properties (HA/TCP ratio, dual porosity and subsequent interconnected architecture) control (regulate/condition) the progressive resorption and the bone substitution process...
January 31, 2017: Acta Biomaterialia
Alexandre Metras, Virginie Fouilloux, Mohammed Al-Yamani, Xavier Roques, Loic Macé, Jean-Benoît Thambo, Dominique Metras, Bernard Kreitmann, François Roubertie
OBJECTIVES: Total cavopulmonary connection (TCPC) performed in the second decade of life has rarely been studied. Thus, we investigated (bicentric study) early and late morbidity and mortality following completion of TCPC in these patients. METHODS: From January 1999 to June 2014, 63 patients (14.5 ± 2.9 years) underwent TCPC (extracardiac conduit). Palliation before completion was an isolated bidirectional cavopulmonary shunt (BCPS) in 3 patients or BCPS associated with additional pulmonary blood flow (APBF) that was either antegrade (Group 1) in 38 (63%) or retrograde (Group 2) in 22 (37%)...
January 25, 2017: Interactive Cardiovascular and Thoracic Surgery
Nataliya R Nichay, Yuriy N Gorbatykh, Igor A Kornilov, Ilya A Soynov, Sergey M Ivantsov, Artem V Gorbatykh, Dmitriy N Ponomarev, Alexander V Bogachev-Prokophiev, Alexander M Karaskov
OBJECTIVES: This study aimed to evaluate the influence of preserved additional pulmonary blood flow (APBF) on survival after bidirectional cavopulmonary shunt (BCPS) and completion of Fontan circulation. METHODS: From March 2003 and April 2015, 156 patients with a single ventricle underwent BCPS. After performing propensity score analysis (1:1) for the entire sample, 50 patients with APBF (APBF group) were matched with 50 patients without APBF (no-APBF group). RESULTS: Age ( P  = 0...
April 1, 2017: Interactive Cardiovascular and Thoracic Surgery
Guan-Wen Yang, Guang-Peng Wu, Xuanxuan Chen, Shisheng Xiong, Christopher G Arges, Shengxiang Ji, Paul F Nealey, Xiao-Bing Lu, Donald J Darensbourg, Zhi-Kang Xu
Directed self-assembly (DSA) of block copolymers (BCPs) combines advantages of conventional photolithography and polymeric materials and shows competence in semiconductors and data storage applications. Driven by the more integrated, much smaller and higher performance of the electronics, however, the industry standard polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) in DSA strategy cannot meet the rapid development of lithography technology because its intrinsic limited Flory-Huggins interaction parameter (χ)...
January 27, 2017: Nano Letters
Ross Lundy, Shauna P Flynn, Cian Cummins, Susan M Kelleher, Maurice N Collins, Eric Dalton, Stephen Daniels, Michael A Morris, Ryan Enright
Molecular self-assembling block copolymers (BCPs) have shown promise as a next generation bottom-up lithography technology. However, a critical step in advancing this approach is the elimination of polymer dewetting due to bulk solvent nucleation and thermodynamically driven film rupture that can occur during the solvent vapor annealing process. We report on the pattern formation via phase segregation of spin coated diblock copolymer films through the investigation of annealing parameters in the limit of high solvent vapor saturation conditions that results in wafer-scale patterning without observing polymer dewetting defects...
January 9, 2017: Physical Chemistry Chemical Physics: PCCP
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